It is envisaged to screen 2600 patients for the presence of ARDS and to include 2400 patients as members of the source population. An in-hospital mortality rate of 30% is assumed; therefore, we expect to analyze a study population of 1500 patients at t1 (discharge from ICU). For each follow-up-assessment (t2-t4: 3 months, 6 months, 12 months after discharge), loss-to-follow-up rates due to death, withdrawal of consent or other reasons are estimated to be about 10%, resulting in slightly more than 1000 patients at 12-months-follow-up.